studio 配置 opencv3.1

环境

win10

android studio2.0

OpenCV-3.1.0-android-sdk

android-ndk-r10e-windows-x86_64

jdk-8u102-windows-x64

1配置ndk环境

补充，这里注意把ndk的环境变量补上，目录设置为ndk的根目录就ok，主要是用来使用ndk-build

2 新建JNI目录

先单选工程目录，然后再点File，否则没那么多选项，找不到创建目录选项

默认生成在app/src/main/jni/

3 在jni中加入Application.mk和Android.mk

Application.mk

APP_STL := gnustl_static                                       //标准c++ stl库

APP_CPPFLAGS := -frtti -fexceptions

APP_ABI := armeabi armeabi-v7a                                 //还可以添加x86等

APP_PLATFORM := android-23                                     //可以不写

Android.mk

LOCAL_PATH := $(call my-dir)

include $(CLEAR_VARS)

OpenCV_INSTALL_MODULES := on

OpenCV_CAMERA_MODULES := off

OPENCV_LIB_TYPE :=STATIC//使用静态库

ifeq ("$(wildcard $(OPENCV_MK_PATH))","")

include D:\soft\OpenCV-android-sdk\sdk\native\jni\OpenCV.mk//这个路径配自己的

else

include $(OPENCV_MK_PATH)

endif

LOCAL_MODULE := OpenCV   //打包so的名称，实际名称是libOpenCV.so  加载时只需要加载OpenCV.so

LOCAL_SRC_FILES := com_n_topencv_OpencvUtils.cpp//要放进so的cpp

LOCAL_LDLIBS +=  -lm -llog

include $(BUILD_SHARED_LIBRARY)

说明：

如果有多个放入so的cpp

可以按如下写法

LOCAL_SRC_FILES := \

	playercore-jni.cpp \

	libplayer.cpp \

	event.cpp \

	lock.cpp \

	receiver.cpp \

	decoder.cpp \

	render.cpp \

	androidaudio.cpp \

	androidvideo.cpp \

	blit.cpp \

	yuv2rgbv7.S

4 工程配置

app下的build.gradle

apply plugin: 'com.android.application'

android {

    compileSdkVersion 23

    buildToolsVersion "23.0.3"

    defaultConfig {

        applicationId "com.n.topencv"

        minSdkVersion 15

        targetSdkVersion 23

        versionCode 1

        versionName "1.0"

        //ndk{

        //    moduleName "OpenCV"         //生成的so名字

        //    abiFilters "armeabi", "armeabi-v7a"  //输出指定三种abi体系结构下的so库。目前可有可无。

        //}

    }

    buildTypes {

        release {

            minifyEnabled false

            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'

        }

    }

    sourceSets {

        main() {

            jniLibs.srcDirs =  ['src/main/libs','src/main/jniLibs']       //把jni库指定为中括号中地址(原地址src/main/jniLibs)默认ndk-build生成so位置为libs

            jni.srcDirs = []                                             //这个如果不设置，.h文件会提示找不到jni.h（这个文件在java sdk的include中）

        }

    }

}

dependencies {

    compile fileTree(dir: 'libs', include: ['*.jar'])

    testCompile 'junit:junit:4.12'

    compile 'com.android.support:appcompat-v7:23.2.1'

}

gradle.properties （补充，之后下载的gradle没这个文件，在gradle/wrapper/下只有gradle-wrapper.properties）

添加一句，这句是使用旧版ndk，否则使用的是实验版构建方式(实验版- -！你懂的)

android.useDeprecatedNdk=true

local.properties

sdk.dir=D\:\\soft\\Android\\sdk

ndk.dir=D\:\\soft\\android-ndk-r10e

5 添加java代码

MainActivity

package com.n.topencv;

import android.app.Activity;

import android.graphics.Bitmap;

import android.graphics.drawable.BitmapDrawable;

import android.media.Image;

import android.support.v7.app.AppCompatActivity;

import android.os.Bundle;

import android.util.Log;

import android.view.Gravity;

import android.widget.FrameLayout;

import android.widget.ImageView;

public class MainActivity extends Activity {

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        Log.e("nafio","OnCreate");

        OpencvUtils opencv = new OpencvUtils();

        Log.e("nafio","InitSo");

        ImageView img = new ImageView(this);

        Bitmap bitmap = ((BitmapDrawable) getResources().getDrawable(

                R.mipmap.ic_launcher)).getBitmap();

        int w = bitmap.getWidth(), h = bitmap.getHeight();

        int[] pix = new int[w * h];

        bitmap.getPixels(pix, 0, w, 0, 0, w, h);

        Log.e("nafio","befor opencv!");

        int [] resultPixes=opencv.gray(pix,w,h);

        Log.e("nafio","after opencv!");

        Bitmap result = Bitmap.createBitmap(w,h, Bitmap.Config.RGB_565);

        result.setPixels(resultPixes, 0, w, 0, 0,w, h);

        //ImageView img = (ImageView) findViewById(R.id.myImageView);

        if(null!=img)img.setImageBitmap(result);

        else{

            Log.e("nafio","null fuck!");

        }

        setContentView(img);

    }

}

OpencvUtils

package com.n.topencv;

/**

 * Created by cuizheng on 2016/8/1.

 */

public class OpencvUtils {

    static {

        System.loadLibrary("OpenCV");   //defaultConfig.ndk.moduleName

    }

    public native int[] gray(int[] pix,int w,int h);

}

xml

<?xml version="1.0" encoding="utf-8"?>

<manifest xmlns:android="http://schemas.android.com/apk/res/android"

    package="com.n.topencv">

    <application

        android:allowBackup="true"

        android:icon="@mipmap/ic_launcher"

        android:label="@string/app_name"

        android:supportsRtl="true"

        android:theme="@style/AppTheme">

        <activity android:name=".MainActivity">

            <intent-filter>

                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />

            </intent-filter>

        </activity>

    </application>

</manifest>

6 添加jni c++代码

com_n_topencv_OpencvUtils.h

这个文件可以自动生成

写完OpencvUtils.java(里面包含有native方法)这个类后，build一下工程，会在

下生成OpencvUtils.class

Terminal进入这个debug文件夹 执行javah -jni com.n.topencv.OpencvUtils

执行成功会在debug下生成com_n_topencv_OpencvUtils.h,把这个头文件copy到jni中

/* DO NOT EDIT THIS FILE - it is machine generated */

#include <jni.h>

/* Header for class com_n_topencv_OpencvUtils */

#ifndef _Included_com_n_topencv_OpencvUtils

#define _Included_com_n_topencv_OpencvUtils

#ifdef __cplusplus

extern "C" {

#endif

/*

 * Class:     com_n_topencv_OpencvUtils

 * Method:    gray

 * Signature: ([III)[I

 */

JNIEXPORT jintArray JNICALL Java_com_n_topencv_OpencvUtils_gray

  (JNIEnv *, jobject, jintArray, jint, jint);

#ifdef __cplusplus

}

#endif

#endif

com_n_topencv_OpencvUtils.cpp

//

// Created by cuizheng on 2016/8/1.

//

#include "com_n_topencv_OpencvUtils.h"

#include <stdio.h>

#include <stdlib.h>

#include <opencv2/opencv.hpp>

using namespace cv;

extern "C" {

JNIEXPORT jintArray JNICALL Java_com_n_topencv_OpencvUtils_gray(

        JNIEnv *env, jobject obj, jintArray buf, int w, int h);

JNIEXPORT jintArray JNICALL Java_com_n_topencv_OpencvUtils_gray(

        JNIEnv *env, jobject obj, jintArray buf, int w, int h) {

    jint *cbuf;

    cbuf = env->GetIntArrayElements(buf, JNI_FALSE );

    if (cbuf == NULL) {

        return 0;

    }

    Mat imgData(h, w, CV_8UC4, (unsigned char *) cbuf);

    uchar* ptr = imgData.ptr(0);

    for(int i = 0; i < w*h; i ++){

        //计算公式：Y(亮度) = 0.299*R + 0.587*G + 0.114*B

        //对于一个int四字节，其彩色值存储方式为：BGRA

        int grayScale = (int)(ptr[4*i+2]*0.299 + ptr[4*i+1]*0.587 + ptr[4*i+0]*0.114);

        ptr[4*i+1] = grayScale;

        ptr[4*i+2] = grayScale;

        ptr[4*i+0] = grayScale;

    }

    int size = w * h;

    jintArray result = env->NewIntArray(size);

    env->SetIntArrayRegion(result, 0, size, cbuf);

    env->ReleaseIntArrayElements(buf, cbuf, 0);

    return result;

}

}

问题说明，这两个文件打开android studio会一直提示，就算点了Sync Now也没用，还是这个提示，不用管，不影响打包和运行

7 用ndk-build打包so

Terminal进入jni文件夹

执行ndk-build，如果执行成功会生成如下文件夹

说明：一旦so包打出来了，jni文件夹就可有可无了，都不影响程序运行

8 运行

一些常见错误报错说明

Error: NDK integration is deprecated in the current plugin. Consider trying the new experimental plugin. For details, see http://tools.android.com/tech-docs/new-build-system/gradle-experimental. Set "android.useDeprecatedNdk=true" in gradle.properties to continue using the current NDK integration.

需要在gradle.properties中添加android.useDeprecateNdk = true;使用旧版的ndk功能（不添加会使用实验性的ndk构建工具）

android studio上写c++头文件，引入jni.h时发现报红，cannot find jni.h

解决方法在app->build.gradle中，android标签中

sourceSets {

        main() {

            jni.srcDirs = [];

        }

    }

Error: Your project contains C++ files but it is not using a supported native build system

这个问题解决方法跟上面类似

gradle.properties中加

Android.useDeprecatedNdk=true



build.gradle(Module:app)中加

sourceSets {

  main {

        jni.srcDirs = []

  }

}